The present invention relates to an explosion-proof catalyst bed for use in catalytic combustion heaters, and to a method for rendering explosion-proof a catalytic heater bed which would otherwise be subject to explosion.
Explosion proof catalytic combustion heaters have been produced in North America since the early 1960's. These heaters use platinum and palladium in various quantities as the active combustion catalyst and these catalysts are impregnated into asbestos carrier material to form a catalyst bed. Catalytic combustion takes place within the catalyst bed when a hydrocarbon fuel such as propane or natural gas mixed with oxygen from the surrounding atmosphere is heated to approximately 250.degree. F. with an electrical element incorporated into the heater. Once the reaction starts, it is self-sustaining until the fuel supply is cut off.
Catalyst beds for these combustion heaters have in the past been made utilizing a special amphibole asbestos carrier material which has served to render the bed explosion-proof when operating in potentially explosive atmospheres.
This amphibole asbestos material is no longer available in suitable form to produce a good quality catalyst bed, and catalyst beds using asbestos material other than this amphibole asbestos or other suitable carrier material are susceptible to explosion when used in areas containing flammable gases and this severely limits the extent of the use of catalytic combustion heaters.